/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.catalina.ssi;

import java.io.IOException;
import java.io.PrintWriter;
import java.text.DecimalFormat;

/**
 * Implements the Server-side #fsize command
 *
 * @author Bip Thelin
 * @author Paul Speed
 * @author Dan Sandberg
 * @author David Becker
 */
public final class SSIFsize implements SSICommand {
	static final int ONE_KILOBYTE = 1024;
	static final int ONE_MEGABYTE = 1024 * 1024;

	/**
	 * @see SSICommand
	 */
	@Override
	public long process(SSIMediator ssiMediator, String commandName,
	                    String[] paramNames, String[] paramValues, PrintWriter writer) {
		long lastModified = 0;
		String configErrMsg = ssiMediator.getConfigErrMsg();
		for (int i = 0; i < paramNames.length; i++) {
			String paramName = paramNames[i];
			String paramValue = paramValues[i];
			String substitutedValue = ssiMediator
					.substituteVariables(paramValue);
			try {
				if (paramName.equalsIgnoreCase("file")
						|| paramName.equalsIgnoreCase("virtual")) {
					boolean virtual = paramName.equalsIgnoreCase("virtual");
					lastModified = ssiMediator.getFileLastModified(
							substitutedValue, virtual);
					long size = ssiMediator.getFileSize(substitutedValue,
							virtual);
					String configSizeFmt = ssiMediator.getConfigSizeFmt();
					writer.write(formatSize(size, configSizeFmt));
				} else {
					ssiMediator.log("#fsize--Invalid attribute: " + paramName);
					writer.write(configErrMsg);
				}
			} catch (IOException e) {
				ssiMediator.log("#fsize--Couldn't get size for file: "
						+ substitutedValue, e);
				writer.write(configErrMsg);
			}
		}
		return lastModified;
	}

	public String repeat(char aChar, int numChars) {
		if (numChars < 0) {
			throw new IllegalArgumentException("Num chars can't be negative");
		}
		StringBuilder buf = new StringBuilder();
		for (int i = 0; i < numChars; i++) {
			buf.append(aChar);
		}
		return buf.toString();
	}

	public String padLeft(String str, int maxChars) {
		String result = str;
		int charsToAdd = maxChars - str.length();
		if (charsToAdd > 0) {
			result = repeat(' ', charsToAdd) + str;
		}
		return result;
	}

	//We try to mimic Apache here, as we do everywhere
	//All the 'magic' numbers are from the util_script.c Apache source file.
	protected String formatSize(long size, String format) {
		String retString = "";
		if (format.equalsIgnoreCase("bytes")) {
			DecimalFormat decimalFormat = new DecimalFormat("#,##0");
			retString = decimalFormat.format(size);
		} else {
			if (size == 0) {
				retString = "0k";
			} else if (size < ONE_KILOBYTE) {
				retString = "1k";
			} else if (size < ONE_MEGABYTE) {
				retString = Long.toString((size + 512) / ONE_KILOBYTE);
				retString += "k";
			} else if (size < 99 * ONE_MEGABYTE) {
				DecimalFormat decimalFormat = new DecimalFormat("0.0M");
				retString = decimalFormat.format(size / (double) ONE_MEGABYTE);
			} else {
				retString = Long.toString((size + (529 * ONE_KILOBYTE))
						/ ONE_MEGABYTE);
				retString += "M";
			}
			retString = padLeft(retString, 5);
		}
		return retString;
	}
}